The present invention relates to automatic analysis apparatus, and more particularly to an automatic analysis apparatus in which a sample is pipetted from a sample container contained in a sample rack, and the sample is reexamined if necessary.
An automatic analysis apparatus for clinical inspection automatically performs analysis and inspection on analyzing items such as bilirubin, protein, GOT, GPT and the like for a sample such as blood, serum, blood plasma, urine and other body liquids. The automatic analysis apparatus has an analyzing unit for measuring a reaction liquid obtained by reacting a sample with a reagent. As to the methods of supplying the sample to the analyzing unit, there are a method in which a plurality of sample containers are mounted on a turntable and each of the sample containers is positioned at a sample pipetting position by intermittently rotating the turntable, and a method in which a sample rack containing sample containers is positioned at a sample pipetting position of an analyzing unit through a transfer line.
An example of the automatic analysis apparatus in which a sample rack is transferred through a transfer line is disclosed, for example, in Japanese Patent Application Laid-Open No. 4-65676 or in Japanese Patent Application Laid-Open No. 6-207943.
The automatic analysis apparatus disclosed in Japanese Patent Application Laid-Open No. 4-65676 is constructed such that a transfer line for transferring a sample rack in one direction and a transfer line for transferring a sample rack in the other direction are arranged in parallel, a sample rack supplied from a rack supply unit is transferred by the transfer line, a sample on the sample rack is pipetted to the analyzing unit at a sample sucking position provided on the transfer line, and the sample rack is placed in a rack collecting unit through the returning line after sampling. Further, in some midpoint of the returning line there is provided a rack standby space for keeping a reference sample for accuracy management on standby. The reference sample rack is periodically transmitted to the transfer line, and the sample rack is returned again to the rack standby by space through the returning line after sampling.
On the other hand, the analysis apparatus disclosed in Japanese Patent Application Laid-Open No. 6-207943 is constructed such that a standby unit for a sample rack is provided near a rack supply unit, a sample rack supplied from the rack supply unit is transferred by a transfer line, a sample is pipetted from the sample rack to the analyzing unit on the transfer line, and the sample rack is transferred to an exit of the returning line after sampling through the returning line. Further, sample racks having a probability of being reexamined are transferred from an exit of the returning line to the standby unit using a robot-hand, and sample racks not having a probability of being reexamined are transferred from the exit of the returning line to a rack collecting unit using the robot-hand. When an instruction of reexamination is made to a sample rack on standby in the standby unit, the corresponding sample rack is transferred to an entrance of a transfer line and pipetting of a sample to be reexamined is performed on the transfer line.
Both of the analysis apparatuses of the prior art disclosed in Japanese Patent Application Laid-Open No. 4-65676 and in Japanese Patent Application Laid-Open No. 6-207943 are constructed such that all the sample racks transferred by the transfer line are transferred through the returning line, and then contained in the standby unit or in the collecting unit.
In the practical work of sampling inspections, the in number of sample racks for general samples which are judged to need to be reexamined is less than the number of sample racks which are judged not to need to be reexamined; therefore, it can be said that a large number of sample racks which may be judged not to need be reexamined are transferred through the returning line.
When the above-mentioned prior art is applied to an automatic analysis apparatus so as to have a reexamination function for general samples, there occurs a problem in that a large number of sample racks are gathered at the exit of the returning line and a complex handling mechanism for solving the problem is required.